To mount a believable defense against third-party browser engines, Apple would need to demonstrate that their browser is more secure than rival browsers. In ord

To mount a believable defense against third-party browser engines, Apple would need to demonstrate that their browser is more secure than rival browsers. In order to persuasively argue a need to ban all rivals, Apple would need to prove that iOS Safari ships and delivers security patches faster, has significantly better security, and that the harm to users from allowing rival browsers is significantly worse than the harm caused by lack of competition. They would need to prove this for each individual browser / browser engine. The evidence points that Safari's security is in fact worse than either Chrome/Edge or Firefox's so that's going to be a hard sell to even prove they are equivalent. Intentional jailbreaking is a problem for Apple, not for Apple's users.